//Either 函子
class Left {
  static of(value) {
    return new Left(value);
  }
  constructor(value) {
    this._value = value;
  }
  map(fn) {
    return this;
  }
}

class Right {
  static of(value) {
    return new Right(value);
  }
  constructor(value) {
    this._value = value;
  }
  map(fn) {
    return Right.of(fn(this._value));
  }
}

let r1 = Left.of(12).map((x) => x + 2);
let r2 = Right.of(12).map((x) => x + 2);

// console.log(r1, r2);

function parseJSON(str) {
  try {
    return Right.of(JSON.parse(str));
  } catch (e) {
    return Left.of({ error: e.message });
  }
}

// let r = parseJSON("{name:zs}");
// console.log(r);
let r = parseJSON('{"name":"zs"}').map((x) => x.name.toUpperCase());
console.log(r);
